JP2003119446A - Acrylic pressure-sensitive adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an acrylic pressure-sensitive adhesive composition that is suitably useful for tentative fixation of curing sheets which are used for coating or processing a relatively large space, for example, ceilings, floors and wall faces. SOLUTION: This acrylic pressure-sensitive adhesive composition comprises (A) an acrylic copolymer that bears an amide group and a hydroxy group, but includes no carboxy group in the molecule and has the glass transition point (Tg) of <=-35 deg.C and (B) a polyisocyanate originating from tolylene diisocyanate as essential components.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention temporarily protects a relatively large portion such as a ceiling, a floor, or a wall surface by protecting a non-painted or untreated portion such as a polypropylene cloth. The present invention relates to a releasable acrylic pressure-sensitive adhesive composition suitable for producing a pressure-sensitive adhesive tape to be used for fixing to, for example, an amide group and a hydroxyl group in a molecule and a carboxyl group. A polyisocyanate compound (B) derived from tolylene diisocyanate and acrylic copolymer (A) that does not contain substantially and has a glass transition temperature (Tg) within a specific range.
The present invention relates to an acrylic pressure-sensitive adhesive composition characterized by comprising as an essential component.

[0002]

2. Description of the Related Art Conventionally, a surface protective material in which a pressure sensitive adhesive layer made of an acrylic copolymer is provided on a substrate such as paper, cloth and plastic film has been widely used. In particular, the pressure-sensitive adhesive tape for fixing the curing sheet requires a strong adhesive force to fix the pressure-sensitive adhesive tape because of the material used for the curing sheet and the size of the sheet when used. The fixing tape can be relatively easily peeled off from the adherend when removing the adhesive tape, and a so-called "adhesive residue" in which a part of the pressure-sensitive adhesive remains on the adherend during peeling does not occur. is necessary.

Usually, a re-peelable acrylic pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive in order not to cause adhesive residue or to prevent the adhesive strength to an adherend from becoming too large with time. It is used by introducing a functional group such as a hydroxyl group or a carboxyl group into a copolymer and crosslinking the copolymer with a crosslinking agent such as a polyisocyanate compound or a metal chelate compound.

However, a pressure-sensitive adhesive obtained by crosslinking a hydroxyl group-introduced acrylic copolymer with a polyisocyanate compound tends to have insufficient adhesive force for use in a pressure-sensitive adhesive tape for fixing a curing sheet. . Further, even if the acrylic copolymer having a carboxyl group introduced therein is cross-linked using a polyisocyanate compound or a metal chelate compound, the cohesive force of the pressure-sensitive adhesive layer obtained is due to the pressure-sensitive adhesive tape for fixing the curing sheet. However, there is a problem in that adhesive residue is likely to occur on the adherend when the fixing tape is removed after use.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention
Excellent for making pressure-sensitive adhesive tape that is used to temporarily fix a curing sheet that protects unpainted parts such as ceilings, floors, and walls when painting or processing them. Removability, that is, an acrylic pressure-sensitive adhesive that has an appropriate adhesive force and excellent cohesive force, and has both excellent reactivity with the polyisocyanate compound when forming the pressure-sensitive adhesive layer and good pot life. As a result of conducting research to obtain an agent composition, for example, 2-ethylhexyl acrylate and butyl acrylate as a main component,
A small amount of amide group and a very small amount of hydroxyl group were introduced into this, and an acrylic copolymer having a glass transition temperature (Tg) of about -60 ° C, which does not substantially contain a carboxyl group, was mixed with tolylene diisocyanate (TDI It was found that an excellent pressure-sensitive adhesive composition having all of these properties can be obtained by crosslinking with a polyisocyanate compound derived from TDI such as the trimethylolpropane adduct of). Continued to complete the present invention.

[0006]

According to the present invention, (A) a glass transition temperature (T) having an amide group and a hydroxyl group in the molecule and substantially no carboxyl group
g) An acrylic pressure-sensitive adhesive composition comprising: an acrylic copolymer having a temperature of −35 ° C. or lower; and (B) a polyisocyanate compound derived from tolylene diisocyanate, as essential components. To be done.

The present invention will be described in detail below.

Acrylic copolymer used in the present invention
(A) has an amide group as an essential component in its molecule. As the content of the amide group in the acrylic copolymer (A), a repeating unit containing an amide group, preferably an amide group having at least one N—H bond is used as the acrylic copolymer (A). It is preferably in the range of 0.5 to 2% by weight, more preferably 1 to 1.5% by weight, based on 100% by weight. When the content of the repeating unit is at least the lower limit value, the obtained pressure-sensitive adhesive layer has sufficient cohesive force and can prevent adhesive residue, and on the other hand, the content of the repeating unit is When it is at most the upper limit value, the pressure-sensitive adhesive layer has a sufficient adhesive force, which is preferable.

The above-mentioned amide group is not particularly limited, but from the viewpoint of good adhesive force, cohesive force, etc. of the pressure-sensitive adhesive layer formed from the obtained pressure-sensitive adhesive composition, the amide group is preferable. It is preferred that the group is an amide group having at least one NH bond. Among such amide groups, the amide group may be an amide group derived from acrylamide and / or methacrylamide, from the viewpoints of easy availability and easy incorporation into an acrylic copolymer in a polymerization reaction. preferable.

Acrylic copolymer used in the present invention
(A) has a hydroxyl group as an essential component together with an amide group in its molecule. The content of the hydroxyl group in the acrylic copolymer (A), the repeating unit containing a hydroxyl group, based on 100 wt% of the acrylic copolymer (A), preferably 0.
It should be in the range of 05 to 1% by weight, and more preferably 0.1 to 0.5% by weight. When the content of the repeating unit is at least the lower limit value, the obtained pressure-sensitive adhesive layer has excellent cohesive force and heat resistance, and is particularly preferable because the cohesive force at high temperature is excellent. On the other hand, when the content of the repeating unit is not more than the upper limit value, the pressure-sensitive adhesive layer has sufficient adhesive force, which is preferable.

The above-mentioned hydroxyl group is not particularly limited, but the glass transition temperature (Tg) of its homopolymer, which is a main monomer for producing the acrylic copolymer (A). It is preferable that the hydroxyl group is a hydroxyl group derived from a hydroxyl group-containing acrylic ester and / or a methacrylic ester from the viewpoint of good copolymerizability with an acrylic ester having a temperature of −50 ° C. or less.

Further, the present inventors have found that the acrylic copolymer (A) used in the present invention needs to contain substantially no carboxyl group. When a carboxyl group is contained, a pressure-sensitive adhesive layer having an excellent balance between cohesive force and adhesive force cannot be obtained, which is not preferable. The term "substantially free from" as used herein means that the acrylic copolymer is not intentionally incorporated, for example, by means such as copolymerization, and the acrylic copolymer is For example, during the polymerization reaction or during the storage / transportation of the obtained copolymer, a part of the acrylic ester monomer or the acrylic copolymer may be hydrolyzed, etc. It does not include such cases.

Further, the acrylic copolymer (A) used in the present invention needs to have a glass transition temperature (Tg) of -35 ° C or lower, preferably -45 ° C or lower, and more preferably -45 ° C or lower. It should be below 55 ° C. If the glass transition temperature (Tg) exceeds the upper limit and is too high, the initial adhesive force of the pressure-sensitive adhesive layer to be obtained is insufficient and it becomes difficult to adhere to an adherend. It may occur, which is not preferable.

Furthermore, the acrylic copolymer (A) used in the present invention has a weight average molecular weight (Mw) of 50 to 10.
It is preferably 0,000, particularly preferably 600,000 to 800,000. When the value of Mw is at least the lower limit value, the pressure-sensitive adhesive layer obtained has a good balance of the adhesive force and cohesive force, and when it is at most the upper limit value, the pressure-sensitive adhesive layer is formed. At the time of coating the pressure-sensitive adhesive composition solution at the time of formation, a suitable coating viscosity can be obtained without significantly lowering the solid content of the composition solution. Since the agent layer can be formed and the amount of the organic solvent that volatilizes does not increase too much, it is preferable in terms of cost and environmental hygiene. Therefore, it is preferable to appropriately select the Mw of the acrylic copolymer within this range. The "weight average molecular weight" of the copolymer in the present invention means a polystyrene-equivalent value measured by the GPC method.

Acrylic copolymer used in the present invention
(A) is generally an acrylic acid ester, or a repeating unit derived from an acrylic acid ester and a methacrylic acid ester, based on the weight of the acrylic copolymer (A) 50
The content is at least wt%. Specifically, the following monomers (a) ~ (d),

(A) represented by the following general formula (1), H ₂ C = CHCOOR ¹ (1) (wherein R ¹ represents a straight chain or branched chain alkyl group having 4 to 10 carbon atoms), Acrylic ester whose glass transition temperature (Tg) of the homopolymer is -50 ° C or lower [hereinafter,
May be referred to as the main monomer (a)] 50-99.45% by weight,

(B) A monomer having an amide group in the molecule [hereinafter sometimes referred to as amide monomer (b) or simply monomer (b)] 0.5 to 2% by weight,

(C) Monomer having a hydroxyl group in the molecule [hereinafter, sometimes referred to as hydroxyl monomer (c) or simply monomer (c)] 0.05 to 1% by weight,

(D) Copolymerizable with the above monomers (a) to (c),
Comonomers other than the monomers (a) to (c) [hereinafter, simply comonomer
(d)) 0 to 49.45% by weight, preferably 100% by weight of the monomers (a) to (d) in total.

The acrylic copolymer (A) used in the present invention is represented by the above-mentioned general formula (1), and its homopolymer has a glass transition temperature (Tg) of -50 ° C. or lower. It is preferable that the monomer (a) is copolymerized as an essential component.

Such an acrylic ester monomer (a)
Examples of include n-butyl acrylate, n-amyl acrylate, n-octyl acrylate, i-octyl acrylate, 2-ethylhexyl acrylate, n-nonyl acrylate, i-nonyl acrylate and the like. Of these, it is preferable to use n-butyl acrylate, i-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate and the like.

The amount of the main monomer (a) used is from the above-mentioned monomers (a) to
As described above, in general, 50% is generally applied to 100% by weight of (d).
It is good to be about 99.45% by weight, preferably 60 to 98.9% by weight, and more preferably about 70 to 98.9% by weight. The monomer
By (a), by appropriately utilizing the range of the amount used, the pressure-sensitive adhesive layer obtained has excellent adhesive strength,
It is preferable because it has excellent adhesiveness to an adherend.

Acrylic copolymer used in the present invention
(A) is preferably a copolymer of the main monomer (a) and the monomer (b) having an amide group in the molecule as an essential component.

Examples of such amide monomer (b) include, for example, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methyl (meth) acrylamide, N
-n-Butoxymethyl (meth) acrylamide, diacetone
Examples thereof include amide group- or substituted amide group-containing monomers such as (meth) acrylamide. Of these,

Preference is given to using amide monomers having at least one NH bond, in particular acrylamide and / or
Alternatively, the use of methacrylamide is preferred.

The amount of the amide monomer (b) used is the above-mentioned monomer.
As described above, the total amount of (a) to (d) is preferably 0.5 to 2% by weight, more preferably 1 to 1.5% by weight. When the amount of the amide monomer (b) used is not more than the upper limit, the pressure-sensitive adhesive layer to be obtained has sufficient adhesive force, which is preferable. The pressure sensitive adhesive layer is preferable because it has sufficient cohesive force and can prevent adhesive residue.

Acrylic copolymer used in the present invention
(A) together with the main monomer (a) and the amide monomer (b),
It is preferable that the monomer (c) having a hydroxyl group in the molecule is copolymerized as an essential component.

Specific examples of such a hydroxyl monomer (c) include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 3-hydroxyethyl (meth) acrylate.
Hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth)
Acrylate, 3-methyl-3-hydroxybutyl (meth) acrylate, 1,1-dimethyl-3-hydroxybutyl (meth)
Hydroxyl groups such as acrylate, 1,3-dimethyl-3-hydroxybutyl (meth) acrylate, 2,2,4-trimethyl-3-hydroxypentyl (meth) acrylate, 2-ethyl-3-hydroxyhexyl (meth) acrylate Inclusion (meta)
Acrylic acid esters can be mentioned.

Of these hydroxyl monomers (c), 2-
Use of hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate is preferable, and 2-hydroxy The use of ethyl (meth) acrylate is particularly preferred.

The amount of the hydroxyl monomer (c) used is, as described above, preferably 0.05 to 1% by weight, more preferably 100% by weight of the total amount of the monomers (a) to (d). 0.1
It is preferably about 0.5% by weight. Hydroxyl monomer
When the amount of (c) used is not more than the upper limit, the pressure-sensitive adhesive layer obtained has a sufficient adhesive force, which is preferable. On the other hand, when it is at least the lower limit value, the pressure-sensitive adhesive layer has excellent cohesive force and heat resistance, and is particularly preferable at high temperature.

Acrylic copolymer used in the present invention
(A), together with the monomers (a) ~ (c), if necessary, copolymerizable with the monomers (a) ~ (c), the monomers (a) ~ (c Comonomers other than) can be copolymerized.

Examples of such a comonomer (d) include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl methacrylate, i-butyl acrylate, t-butyl acrylate, stearyl acrylate, oleyl acrylate, The above monomers (a) such as cyclohexyl acrylate and benzyl acrylate
Acrylic ester monomers other than; for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, stearyl methacrylate, oleyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, etc. Pre-methacrylic acid ester monomer;

Saturated fatty acid vinyl ester monomers such as vinyl formate, vinyl acetate, vinyl propionate, "vinyl versatate" (trade name: manufactured by Shell Co.); for example, dibutyl maleate, dibutyl fumarate, dibutyl itaconate. , Straight-chain or branched alkyl esters of α, β-unsaturated dicarboxylic acids having 1 to 13 carbon atoms, such as dioctyl malate, dioctyl fumarate, and dioctyl itaconate; for example, styrene, α-methylstyrene, vinyltoluene, ethyl Aromatic vinyl monomers such as vinylbenzene; vinyl cyanide monomers such as (meth) acrylonitrile; and the like.

Further, the comonomer (d) is a monomer having at least one functional group in addition to one radical-polymerizable unsaturated group in the molecule, if necessary. It is also possible to copolymerize a monomer other than the monomers (b) and (c) (hereinafter sometimes referred to as a functional comonomer).

As such a functional comonomer, a monomer having as a functional group, for example, an amino group or a substituted amino group, a lower alkoxyl group having a terminal alkyl group having 6 or less carbon atoms, an epoxy group, or the like. Further, a monomer having two or more radically polymerizable unsaturated groups in the molecule can also be used.

Specific examples of these functional comonomers include:
Aminoethyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate (preferably N, N-dimethylaminoethyl methacrylate, N , N-diethylaminoethylmethacrylate) and other amino group- or substituted amino group-containing monomers;

For example, 2-methoxyethyl acrylate,
2-ethoxyethyl acrylate, 2-n-butoxyethyl acrylate, 2-methoxyethoxyethyl acrylate,
2-ethoxyethoxyethyl acrylate, 2-n-butoxyethoxyethyl acrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-n-butoxyethyl methacrylate, 2-methoxyethoxyethyl methacrylate, 2-ethoxyethoxyethyl methacrylate, 2-n-butoxyethoxyethyl methacrylate, methoxy polyethylene glycol monoacrylate, methoxy polyethylene glycol monomethacrylate, (preferably 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-methoxyethyl methacrylate,
2-ethoxyethyl methacrylate, methoxy polyethylene glycol monoacrylate, methoxy polyethylene glycol monomethacrylate) and other lower alkoxy group-containing monomers;

For example, epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, glycidyl allyl ether, and glycidyl methallyl ether (preferably glycidyl acrylate and glycidyl methacrylate); for example, divinylbenzene, diallyl phthalate, triallyl cyanurate, and triaryl cyanurate. Allyl isocyanurate, ethylene glycol di (meth) acrylate, 1,
2-propylene glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, trimethylolpropane tri (meth)
Examples thereof include monomers having two or more radically polymerizable unsaturated groups such as acrylate and allyl (meth) acrylate.

The amount of the comonomer (d) used is as described above based on 100% by weight of the total of the monomers (a) to (d).
Generally 0 to 49.45% by weight, preferably 0 to 38.9% by weight,
More preferably, it is 0 to 28.9% by weight. The comonomer (d)
When the amount used is less than or equal to the upper limit value, a pressure-sensitive adhesive layer having a good balance of cohesive strength, adhesive strength and heat resistance can be obtained, which is preferable.

The acrylic copolymer used in the present invention
The polymerization method of (A) is not particularly limited, but usually solution polymerization is preferably used.

In the solution polymerization, generally, a predetermined organic solvent, a monomer, a polymerization initiator, and optionally a chain transfer agent are charged in a polymerization tank, and the mixture is supplied in a nitrogen stream or at the reflux temperature of the organic solvent. The reaction is carried out by heating for several hours while stirring. In this case, at least a part of the organic solvent, the monomer, the polymerization initiator and / or the chain transfer agent may be sequentially added.

Examples of the organic solvent for polymerization include, for example,
Benzene, toluene, ethylbenzene, n-propylbenzene, t-butylbenzene, o-xylene, m-xylene, p-
Aromatic hydrocarbons such as xylene, tetralin, decalin and aromatic naphtha; for example, n-hexane, n-heptane, n-
Fatty or alicyclic hydrocarbons such as octane, i-octane, n-decane, dipentene, petroleum spirit, petroleum naphtha, turpentine oil; for example, ethyl acetate, n-butyl acetate, n-amyl acetate, acetic acid 2 -Hydroxyethyl, 2-butoxyethyl acetate, 3-methoxybutyl acetate, methyl benzoate, etc. esters; for example, acetone, methyl ethyl ketone, methyl-i-butyl ketone, isophorone, cyclohexanone, methylcyclohexanone, etc. ketones; be able to. These organic solvents may be used alone or in combination of two or more.

Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-t-butyl peroxide, di-i-propyl peroxydicarbonate, di-2-ethylhexyl peroxy. Organic peroxides such as dicarbonate and t-butyl peroxybivalate; for example, 2,2'-azobis-i-butyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'- Azo compounds such as azobis-4-methoxy-2,4-dimethylvaleronitrile; and the like can be used alone or in combination.

The amount of the polymerization initiator used is generally about 100 parts by weight of the total amount of the monomers (a) to (d) used for the copolymerization.
It can be in the range of 0.01 to 5 parts by weight, preferably about 0.02 to 2 parts by weight.

Examples of the chain transfer agent include:
Cyanoacetic acid; alkyl group having 1 to 8 carbon atoms, cyanoacetic acid alkyl ester; bromoacetic acid; alkyl group having 1 to 8 carbon atoms
Aromatic compounds such as anthracene, phenanthrene, fluorene and 9-phenylfluorene; p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, p-
Aromatic nitro compounds such as nitrotoluene; Benzoquinone, benzoquinone derivatives such as 2,3,5,6-tetramethyl-p-benzoquinone;

Borane derivatives such as tributylborane; carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane,
Halogenated hydrocarbons such as tribromoethylene, trichloroethylene, bromotrichloromethane, tribromomethane, and 3-chloro-1-propene; aldehydes such as chloral and furaldehyde; alkylmercaptans having 1 to 18 carbon atoms; thiophenol, Aromatic mercaptans such as toluene mercaptan; mercaptoacetic acid; alkyl esters of mercaptoacetic acid having 1 to 10 carbon atoms; 1 carbon atom
~ 12 hydroxyalkyl mercaptans; terpenes such as binene and terpinolene.

The amount of the chain transfer agent used is not particularly limited, but is preferably about 0.005 to 3.0 parts by weight per 100 parts by weight of the total of the monomers (a) to (d). .

The polymerization temperature is generally about 30 to 180 ° C,
It is preferably in the range of about 60 to 150 ° C.

When the unreacted monomer is contained in the polymer obtained by the solution polymerization method or the like, it can be purified by the reprecipitation method with methanol or the like in order to remove the monomer. Is.

The acrylic pressure-sensitive adhesive composition of the present invention contains, as an essential component, a polyisocyanate compound (B) derived from tolylene diisocyanate as a cross-linking agent together with the above-mentioned acrylic copolymer (A). It consists of

Such a polyisocyanate compound (B)
Is derived from, for example, 2,4-tolylene diisocyanate or 2,6-tolylene diisocyanate, or tolylene diisocyanate which is a mixture thereof. As the polyisocyanate compound, in addition to those derived from the tolylene diisocyanate, those derived from various polyisocyanates such as xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate are known. As a result of the research, it is necessary to use one derived from tolylene diisocyanate as an essential component because of the good reactivity with the acrylic copolymer (A) containing an amide group as an essential component in the molecule. I knew that.

Examples of the polyisocyanate compound (B) derived from tolylene diisocyanate include adducts of tolylene diisocyanate with polyhydric alcohols such as water, ethylene glycol and trimethylol propane, particularly trimethylol propane. Adducts are especially preferred.

The content of the polyisocyanate compound (B) is not necessarily limited, but preferably,
The amount is preferably 0.15 to 1.1 equivalents, particularly 0.2 to 1 equivalents, relative to 1 equivalent of the reactive functional group in the acrylic copolymer (A).

The acrylic pressure-sensitive adhesive composition of the present invention comprises
Acrylic copolymer (A) and a polyisocyanate compound derived from tolylene diisocyanate (B), and if necessary, for example, coumarone / indene resin, terpene / phenol resin, rosin resin, pt-
A tackifier (C) such as butylphenol / acetylene resin, phenol / formaldehyde resin, xylene / formaldehyde resin, petroleum hydrocarbon resin, hydrogenated hydrocarbon resin, and turpentine resin can be added. Of these tackifiers (C), from the viewpoint of good adhesion to adherends, etc., it is preferable to use rosin-based resins; from the viewpoint of good weather resistance, the use of petroleum-based hydrocarbon resins, either alone or It is more preferable to use them in combination.

Examples of the rosin-based resin that can be preferably used in the present invention include rosin esters and hydrogenated rosin esters.

Here, the rosin ester is obtained by esterifying a raw material rosin of gum rosin, wood rosin or tall oil rosin or a stabilized rosin obtained by disproportionating or hydrogenating the raw material rosin with a polyhydric alcohol. Polyhydric alcohol ester of polymerized rosin, partially fumarized or maleated raw rosin, and then esterified to obtain partially maleated rosin polyhydric alcohol ester, partially fumarized rosin polyhydric alcohol ester, , A polyhydric alcohol ester of a partially maleated disproportionated rosin obtained by partially fumarizing or maleating a raw material rosin, and then esterifying it, a polyhydric alcohol of a partially fumarized disproportionated rosin Refers to ester and the like.

The softening point of the tackifier (C) that can be preferably used in the present invention is preferably 90 to 180 ° C., more preferably 100 to 140 ° C., and particularly preferably 115 to 125 ° C. . If the softening point of the tackifier is at least the lower limit value, it is preferable that the resulting pressure-sensitive adhesive layer does not cause inconveniences such as a decrease in cohesive force. It is preferable because the improvement of The softening point of the tackifier is a value measured according to the ring and ball method of JIS K 2531.

The tackifier (C) that can be preferably used in the present invention has a weight average molecular weight (Mw) of 5000 or less, and particularly preferably 1000 to 4000. When the value of Mw is not more than the upper limit value, the pressure-sensitive adhesive layer obtained has excellent adhesive physical properties such as normal-state adhesive strength, low-temperature adhesive strength, and curved surface adhesiveness, which is preferable. On the other hand, when it is at least the lower limit value, the decrease in cohesive force of the obtained pressure-sensitive adhesive layer is small, which is preferable. The Mw of the tackifier (C) is a polystyrene-equivalent value measured by the GPC method as in the case of the acrylic copolymer (A) used in the present invention.

Examples of commercially available tackifiers (C) that can be suitably used in the present invention include superester A-115, Pencel D-125, ester gum H [above Arakawa Chemical Industry Co., Ltd. )), Harrier Star DS-90S (Harima Kasei Co., Ltd.), Rikatak F105, Rikatak PCJ (above)
Manufactured by Rika Finetech Co., Ltd .;
Petroleum hydrocarbon resin such as FTR-6100 (manufactured by Mitsui Chemicals, Inc.);
For example, YS Polystar T-115, Mighty Ace G-125
Terpene phenolic resins such as those manufactured by Yasuhara Chemical Co., Ltd .; for example, Nikanol H-80, Nikanol HP-100
Xylene resins such as those manufactured by Mitsubishi Gas Chemical Co., Ltd .; for example, Hitachinol 1501 manufactured by Hitachi Chemical Co., Ltd., cash register top PS
-4901 [manufactured by Gunei Chemical Co., Ltd.] and the like, which are commercially available under the trade names such as alkylphenol resins.

The acrylic pressure-sensitive adhesive composition of the present invention comprises a polyisocyanate compound (B) derived from the above acrylic copolymer (A) and tolylene diisocyanate,
And a tackifier (C) that can be used if necessary
In addition, if desired, various additives can be further contained. Examples of such additives include pigments, dyes, ultraviolet absorbers, antioxidants and the like.

As a method for forming a pressure-sensitive adhesive layer using the acrylic pressure-sensitive adhesive composition of the present invention, the pressure-sensitive adhesive composition is diluted to a coatable viscosity, and this is diluted with paper,
The direct method of removing the solvent by directly coating and drying on a substrate such as cloth or plastic film; first, the pressure-sensitive adhesive is applied onto a release sheet such as paper or plastic film which has been subjected to a release treatment with a silicone resin or the like. An indirect method in which the composition is applied to an appropriate thickness, heated and dried to form a pressure-sensitive adhesive layer, and transferred to paper or a plastic film, preferably a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, or vinyl chloride. Can be illustrated.

[0062]

EXAMPLES The present invention will be described in more detail with reference to Examples, Comparative Examples and Reference Examples. Incidentally, the pot life of the pressure-sensitive adhesive composition, the preparation of the test pressure-sensitive adhesive sheet,
The methods for measuring various physical properties such as adhesive strength and cohesive strength are as follows.

[0063](1) Preparation of pressure-sensitive adhesive sheet for testing Polyethylene cloth sheet with a thickness of about 80 μm [Kikusui tape
Co., Ltd.], and after drying the sample of the pressure-sensitive adhesive composition
The dry coating amount is about 45 g / m²And apply at 80 ℃
Dry with a hot air circulation dryer for 2 minutes to make a pressure-sensitive adhesive sheet
And then cured for 7 days at 23 ° C and 65% RH
Is used as a test pressure-sensitive adhesive sheet.

[0064](2) Measurement of initial adhesive strength SUS 30 polished with # 360 water resistant abrasive paper specified in JIS R-6253
4 stainless steel plate (hereinafter sometimes abbreviated as SUS)
And polyvinyl chloride board (Kapai gray manufactured by Kasai Sangyo)
The test pressure-sensitive adhesive sheet prepared in (1) above.
Test the test piece by pressing it according to JIS Z-0237.
For 30 minutes under the conditions of 23 ℃ and 50% RH.
After placing, place at 23 ℃, 50% RH, peeling speed 300mm / min.
Measure the adhesive strength (N / 25mm) at 180 ° peeling.

The initial adhesive force is, for example, preferably 5 to 10 N / 25 mm, particularly preferably 7 to 9 N / 25 mm.

[0066](3) Curing test Test sample prepared in the same manner as in the previous section (2), 65 ℃, 80% RH
Left for 2 days at 23 ° C and 50% RH
After leaving for 1 hour, peeling by hand, and the surface of the adherend after peeling
The condition of is visually observed and evaluated according to the following criteria.
It was

(Evaluation criteria) ⊚: No cloudiness or adhesive residue can be found. ○: There is a slight amount of cloudiness, and no adhesive residue can be found. Δ: Adhesive residue is slightly observed. X: Adhesive residue is found in most of the areas.

[0068](4) Measuring holding force Tests made in (1) above on a SUS plate treated in the same way as in (2) above.
The test piece cut out from the pressure-sensitive adhesive sheet for
Stick it so that the product is 25 x 25 mm, and use a 2 kg roller for 10
I crimped back and forth. 1kg static load in a constant temperature bath at 40 ℃
Time (minutes) until the load is dropped on the sample and the load falls or
Measure the deviation width (mm) after 1000 minutes.

[0069]Preparation of acrylic copolymer Production example 1 An agitator, reflux condenser, sequential dropping device, and thermometer
In the reaction equipment, ethyl acetate (EA
c) 53 parts by weight and, as a polymerization initiator, azobisisobutyrate
Add 0.01 parts by weight of ronitrile (AIBN), then another container
2-ethylhexyl acrylate as the main monomer (a)
(EHA) 49.6 parts by weight and n-butyl acrylate (BA) 49
Parts by weight, acrylamide (AAm) as amide monomer (b)
1.2 parts by weight, and 2-hydr as the hydroxyl monomer (c)
Roxyethyl acrylate (HEA) 0.2 parts by weight
6.7 parts by weight of acetone were mixed with the monomer mixture, of which 40
Add wt% to the reactor and then heat the contents to the reflux temperature.
Polymerization was performed at a temperature (about 80 ° C.) for about 30 minutes. Then the reflux temperature
Under the conditions, the residual amount of the monomer mixture is 60% by weight and toluene is 3.3%.
And a polymerization initiator solution consisting of 0.1 part by weight of AIBN.
Sequentially drop for about 90 minutes and react for 90 minutes.
15 minutes by weight of toluene and 0.25 parts by weight of AIBN for about 40 minutes.
Parts of the polymerization initiator solution are added dropwise for another 120 minutes.
The polymerization reaction was continued. After the reaction is complete, add toluene
Dilute and adjust to a solid content of 50% by weight to obtain a viscosity of 18500 mPa · s (B
Type viscometer, 25 ° C, 10 rpm; viscosity measurement conditions are the same below)
An acrylic copolymer solution was obtained. The Mw of this copolymer is
About 760,000, Tg was -66 ° C.

Production Examples 2 to 4 In Production Example 1, as shown in Table 1, the amide monomer (b)
The amount of AHAm is changed or the amount of HEA which is a hydroxyl monomer (c) is increased without using it, and the amount of EHA of the main monomer (a) is adjusted as necessary. An acrylic copolymer solution was obtained in the same manner as in Production Example 1 except for the above. Table 1 shows the monomer composition used, the viscosity of the obtained copolymer solution, and the values of Tg and Mw of the copolymer.

Production Examples 5 to 7 In Production Example 1, the amount of HEA used as the hydroxyl monomer (c) was changed as shown in Table 1 or the amide monomer (b) was used without using it. An acrylic copolymer solution was obtained in the same manner as in Production Example 1 except that the amount of AAm used was increased and the amount of EHA of the main monomer (a) was adjusted as necessary. Table 1 shows the monomer composition used, the viscosity of the obtained copolymer solution, and the values of Tg and Mw of the copolymer.

Production Example 8 Acrylic acid was produced in the same manner as in Production Example 1 except that 0.5% by weight of acrylic acid (AA) was used and the amount of EHA used as the main monomer (a) was reduced. A system copolymer solution was obtained. Table 1 shows the monomer composition used, the viscosity of the obtained copolymer solution, and the values of Tg and Mw of the copolymer.

Production Examples 9 to 12 In Production Example 1, as shown in Table 1, either EHA or BA as the main monomer (a) was used, or the main monomer was used.
Same as Production Example 1 except that only BA was used as (a) and methyl acrylate (MA) or methyl methacrylate (MMA) was used as the comonomer (d) to change the Tg of the copolymer. An acrylic copolymer solution was obtained. Table 1 shows the monomer composition used, the viscosity of the obtained copolymer solution, and the values of Tg and Mw of the copolymer.

Production Example 13 Instead of sequentially dropping the polymerization initiator solution consisting of 3.3 parts by weight of toluene and 0.1 part by weight of AIBN in Production Example 1 over about 90 minutes, 16.5 parts by weight of toluene and 0.1 parts by weight of AIBN were added.
An acrylic copolymer solution having an Mw of about 400,000 was obtained in the same manner as in Production Example 1 except that the polymerization initiator solution consisting of parts by weight was successively added dropwise over about 90 minutes. Table 1 shows the monomer composition used, the viscosity of the obtained copolymer solution, and the values of Tg and Mw of the copolymer.

Production Example 14 In Production Example 1, 53% of EAc was used as the organic solvent for initial addition.
Instead of using 35 parts by weight of EAc, 35 parts by weight of EAc was used.
Instead of sequentially dropping the polymerization initiator solution consisting of 3.3 parts by weight and AIBN 0.1 part by weight over about 90 minutes, successively add the polymerization initiator solution consisting of 1.65 parts by weight of toluene and 0.1 part by weight of AIBN over about 90 minutes. Production Example 1 except
In the same manner as above, an acrylic copolymer solution having Mw of about 1.1 million was obtained. Table 1 shows the monomer composition used, the viscosity of the obtained copolymer solution, and the values of Tg and Mw of the copolymer.

[0076]

[Table 1]

[0077]Preparation of acrylic pressure-sensitive adhesive composition Example 1 200 weight of acrylic copolymer (A) solution obtained in Production Example 1
Parts [about 100 parts by weight as acrylic copolymer; functional group
(Amide group and hydroxyl group) 0.01863 equivalent parts in total
(In addition, "equivalent part" was replaced by 100 g by 100 g.
The equivalent number of time))]
Cyanate compound (B) "Coronate L" [Tolylene diiso
C containing trimethylolpropane adduct of cyanate
Retan prepolymer; solid content 75% by weight, NCO content 13.2
% By weight; manufactured by Nippon Polyurethane Co., Ltd.] 3.0 parts by weight [0.00943
Equivalent part; to 1 equivalent of the functional group in the acrylic copolymer (A)
Approximately 0.506 equivalents], a rosin-based tackifier as a tackifier (C).
Adhesion imparting agent ["Super Ester A-115"; solid content 100 weight
%, Softening point 115 ° C., Mw about 1240; manufactured by Arakawa Chemical Industries, Ltd.) (A
-115) diluted with toluene to 50% 32 parts by weight (solid)
16 parts by weight) are mixed by stirring to obtain a solid content of about 50% by weight and a viscosity of 98.
An acrylic pressure-sensitive adhesive composition of 00 mPa · s was obtained.

Using the pressure-sensitive adhesive composition thus obtained, a pressure-sensitive adhesive sheet was prepared according to the method described above, and various physical properties were tested. Table 3 shows the results of various physical property tests of the pressure-sensitive adhesive sheet.

Examples 2 to 3 Similar to Example 1 except that the isocyanate cross-linking agent (B) "Coronate L" was used in 3.0 parts by weight, but the amount used was changed as shown in Table 2. Then, an acrylic pressure-sensitive adhesive composition was obtained, and various physical property tests were conducted in the same manner. The composition of the pressure sensitive adhesive composition is shown in Table 2.
Table 3 shows the solid content and viscosity, which are characteristic values of the obtained pressure-sensitive adhesive composition, and various physical property test results of the pressure-sensitive adhesive sheet.

Comparative Examples 1 and 2 Instead of using "Coronate L" as the polyisocyanate compound (B) in Example 1, a polyisocyanate compound "Coronate HL" [a urethane preform composed of a trimethylolpropane adduct of hexamethylene diisocyanate] was used. Polymer; solid content 75% by weight, NCO content 12.8% by weight; manufactured by Nippon Polyurethane Co., Ltd.] 3.1 parts by weight [0.00945 equivalents; about 0.507 with respect to 1 equivalent of functional group in acrylic copolymer (A)] Equivalent] or the polyepoxy compound "TETRAD-
C "[1,3-bis (N, N-diglycidylaminomethyl) cyclohexane; solid content 100% by weight; manufactured by Mitsubishi Gas Chemical Co., Inc.] (T
ET-C) 2.4 parts by weight [0.00938 equivalents; acrylic copolymer
An acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that about 0.503 equivalents relative to 1 equivalent of the functional group in (A) was used, and various physical property tests were conducted in the same manner. . Table 2 shows the composition of the pressure-sensitive adhesive composition, and Table 3 shows the solid content and viscosity, which are characteristic values of the obtained pressure-sensitive adhesive composition, and various physical property test results of the pressure-sensitive adhesive sheet.

Examples 4 to 5 Instead of using 16 parts by weight of a rosin-based tackifier (A-115) as the tackifier (C) in Example 1, styrene /
Aliphatic hydrocarbon copolymer resin tackifier ["FTR-611
0 ”; solid content 100% by weight, softening point 110 ° C., Mw about 1570; Mitsui Chemicals, Inc.] (FTR-6110) 32 parts by weight diluted with toluene (solids content 16 parts by weight) or Styrene / aliphatic hydrocarbon copolymer resin tackifier [“FTR-6125”; solid content 100% by weight, softening point 125 ° C., Mw about 1950; Mitsui Chemicals, Inc.
Manufactured by (FTR-6125) diluted with toluene to 50% by weight 20
An acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that parts by weight (solid content: 10 parts by weight) were used, and various physical property tests were conducted in the same manner. Table 2 shows the composition of the pressure-sensitive adhesive composition, and Table 3 shows the solid content and viscosity, which are characteristic values of the obtained pressure-sensitive adhesive composition, and various physical property test results of the pressure-sensitive adhesive sheet.

Examples 6 to 14 and Comparative Examples 3 to 6 In Example 1, instead of using the acrylic copolymer solution of Production Example 1, any of Production Examples 2 to 14 was used. Example 1 except that "Coronate L" was added so that the number of equivalents of "Coronate L" per equivalent of total functional groups of the polymer was about the same as the value of Example 1.
In the same manner as above, an acrylic pressure-sensitive adhesive composition was obtained, and various physical property tests were carried out in the same manner. Table 2 shows the composition of the pressure-sensitive adhesive composition, and Table 3 shows the solid content and viscosity, which are characteristic values of the obtained pressure-sensitive adhesive composition, and various physical property test results of the pressure-sensitive adhesive sheet.

[0083]

[Table 2]

[0084]

[Table 3]

[0085]

The acrylic pressure-sensitive adhesive composition of the present invention has an amide group and a hydroxyl group in the molecule and substantially no carboxyl group, and has a specific glass transition temperature (Tg). The acrylic copolymer (A) and the polyisocyanate compound (B) derived from tolylene diisocyanate in the range are contained as essential components.

The acrylic pressure-sensitive adhesive composition of the present invention comprises
By being configured as described above, it has excellent performance that combines excellent reactivity with a polyisocyanate compound and good pot life, and particularly, ceiling, floor,
A pressure-sensitive adhesive layer with excellent removability suitable for making a pressure-sensitive adhesive tape used for temporarily fixing a curing sheet used for coating or processing a relatively large part such as a wall surface. It can be preferably used for forming.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masami Uemae             53 Yoneyama Minami-cho, Sano City, Tochigi Prefecture Japan Carbide             Kogyo Co., Ltd. F term (reference) 4J034 BA03 DB01 DB03 GA15 GA33                       GA34 HA01 HA02 HA06 HA07                       HA08 HC03 HC12 HC22 HC52                       HC61 HC63 HC64 JA01 SA01                       SA02 SA05 SB04                 4J040 DF041 DF051 EF111 EF231                       EF281 EF291 EF301 GA05                       GA08 GA11 GA14 GA20 GA22                       HB41 JA13 JB09 KA16 KA18                       KA23 KA26 LA01 LA06 LA08                       NA12 PA30 PA33

Claims (12)

[Claims] 1. The following (A) and (B): (A) at a glass transition temperature (Tg) of −35 ° C. or lower, which contains an amide group and a hydroxyl group in the molecule and does not substantially contain a carboxyl group. An acrylic copolymer; and
(B) A polyisocyanate compound derived from tolylene diisocyanate; as an essential component, an acrylic pressure-sensitive adhesive composition. 2. The acrylic copolymer (A) contains a repeating unit derived from a (meth) acrylic acid ester in an amount of 50% by weight or more based on the weight of the acrylic copolymer (A). The pressure-sensitive adhesive composition according to claim 1, which is one. 3. The acrylic copolymer (A) contains a repeating unit containing an amide group in an amount of 0.5 to 2% by weight based on the weight of the acrylic copolymer (A). The pressure-sensitive adhesive composition according to claim 1. 4. The pressure-sensitive adhesive composition according to claim 1, wherein the amide group is an amide group having at least one N—H bond. 5. The pressure-sensitive adhesive composition according to claim 1, wherein the amide group is an amide group derived from (meth) acrylamide. 6. The acrylic copolymer (A) comprises a repeating unit containing a hydroxyl group, the acrylic copolymer
The pressure-sensitive adhesive composition according to claim 1, which comprises 0.05 to 1% by weight based on the weight of (A). 7. The pressure-sensitive adhesive composition according to claim 1, wherein the hydroxyl group is a hydroxyl group derived from a hydroxyl group-containing (meth) acrylic acid ester. 8. The acrylic copolymer (A) is the following monomer (a)
~ (D), (a) represented by the following general formula (1), H ₂ C = CHCOOR ¹ (1) (wherein R ¹ represents a straight-chain or branched-chain alkyl group having 4 to 10 carbon atoms) Acrylic ester whose homopolymer has a glass transition temperature (Tg) of -50 ° C or lower
9.45% by weight, (b) 0.5 to 2% by weight of a monomer having an amide group in the molecule, (c) 0.05 to 1 of a monomer having a hydroxyl group in the molecule
% By weight, (d) copolymerizable with the above monomers (a) to (c), the monomer (a)
To 0. 49.45% by weight of a comonomer other than (a) to (c), provided that the total amount of the monomers (a) to (d) is 100% by weight). The pressure-sensitive adhesive composition according to item 1. 9. The feeling according to claim 1, wherein the content of the polyisocyanate compound (B) is in the range of 0.2 to 1.2 equivalents relative to 1 equivalent of the reactive functional group in the acrylic copolymer (A). Pressure-adhesive composition. 10. The pressure-sensitive adhesive composition according to claim 1, wherein the polyisocyanate compound (B) is an adduct of tolylene diisocyanate and a polyhydric alcohol. 11. The pressure sensitive adhesive composition further comprises a tackifier.
The pressure-sensitive adhesive composition according to claim 1, which contains (C). 12. The pressure-sensitive adhesive composition according to claim 11, wherein the content of the tackifier (C) is in the range of 5 to 20 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). object.